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Finding the Fourth Proportional to 720.15, 993.80 and 405.42

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Solution

The fourth proportional to 720.15, 993.80 and 405.42 is: 559.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.15 : 993.80 = 405.42 : x
  2. Step 2: Convert to fraction form
    720.15/993.80 = 405.42/x
  3. Step 3: Cross multiply
    720.15x = 993.80 × 405.42
  4. Step 4: Simplify right side
    720.15x = 402,899.40
  5. Step 5: Solve for x
    x = 402,899.40/720.15
  6. Step 6: Final answer
    x = 559.47

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.